WO2018028265A1 - Wavelength conversion device and preparation method therefor, light-emitting device and projection device - Google Patents

Abstract

Provided are a wavelength conversion device (10) and a preparation method therefor, a light-emitting device and a projection device. The wavelength conversion device (10) comprises: a light-emitting ceramic (12) and scattering particles (11), wherein the scattering particles (11) are uniformly dispersed in the light-emitting ceramic (12); the particle size of the scattering particles (11) is 10 nm - 5000 nm, and the volume fraction of the scattering particles (11) in the wavelength conversion device (10) is 1% - 60%; the light-emitting ceramic (12) is an oxide ceramic with a garnet structure; and the light-emitting ceramic (12) contains a doped ion in a doping amount of 0.01% - 1%. The wavelength conversion device (10) has beneficial effects such as a high thermal stability and a light saturation phenomenon resistance.

Description

Wavelength conversion device, preparation method thereof, illumination device and projection device Technical field

The present invention relates to the field of illumination and projection technologies, and in particular, to a wavelength conversion device, a method of fabricating the same, a light-emitting device, and a projection device.

Background technique

With the development of display and lighting technology, the original halogen bulb as a light source is increasingly unable to meet the high power and high brightness requirements of display and illumination. The use of excitation light from a solid-state light source such as an LD (Laser Diode) to excite a wavelength-converting material can obtain visible light of various colors, and this technology is increasingly used in illumination and display. This technology has the advantages of high efficiency, low energy consumption, low cost and long life, and is an ideal alternative to existing white or monochromatic light sources.

At present, the packaging method of the phosphor is mainly composed of an organic silicone package and an inorganic glass package. The thermal conductivity of the two packages is low (1 W/(m·K) or less), and the thermal damage resistance temperature is not high. The withstand temperature is generally below 200 ° C, and the glass withstand temperature is generally below 600 ° C. The traditional packaging method can not meet the current application of high-power excitation light source.

Another type of phosphor in the prior art is packaged in a ceramic package. For example, at present, YAG luminescent ceramics are mainly packaged in two ways. One is that YAG phosphor powder is mixed with thermal conductive powder Al ₂ O _{3 to} form a composite luminescent ceramic, and the degree of scattering is adjusted by alumina to improve the luminescent ceramic to the excitation light. Absorption probability, but the concentration of Ce ^{3+ in the} YAG phosphor is higher, the thermal stability is poor, and it is easy to appear luminescence saturation under the excitation of high-power blue light excitation; the other is to use alumina, yttrium oxide, oxidation The raw material (doping concentration of 3% or more) is mixed and sintered to form a pure phase luminescent ceramic. The thermal stability of the luminescent ceramic prepared by this method is improved, but the Ce ³⁺ doping concentration is still too high, and the thermal stability cannot satisfy the high power. The application of excitation light; at the same time, this method can also control the degree of scattering by the pore-forming agent, but the thermal conductivity of the porous structure of the luminescent ceramic is low, and the structural strength is poor when the sheet is produced. Therefore, how to improve the thermal stability of the luminescent ceramic, avoid the saturation phenomenon of the luminescent efficiency, and ensure the good mechanical strength of the luminescent ceramic is a problem to be solved in the art.

Summary of the invention

In view of the above technical problems, the present invention provides a wavelength conversion device having high thermal stability, light saturation resistance and high mechanical strength suitable for high power excitation light source applications.

The invention provides a wavelength conversion device, comprising:

The wavelength conversion device includes luminescent ceramics and scattering particles, the scattering particles are uniformly dispersed in the luminescent ceramic; the scattering particles have a particle diameter of 10 nm to 5000 nm, and a volume fraction of the scattering particles in the wavelength conversion device The luminescent ceramic is an oxidized ceramic of garnet structure; and the luminescent ceramic contains doping ions having a doping amount of 0.01% to 1%.

Preferably, the luminescent ceramic has a thickness of 50 um to 500 um.

Preferably, the luminescent ceramic is in Ca ₃ (Al, Sc) ₂ Si ₃ O ₁₂ , (Gd, Tb, Y, Lu) ₃ (Al, Ga) ₅ O ₁₂ or Y ₃ Mg ₂ AlSi ₂ O ₁₂ At least one of; the scattering particles are at least one of alumina, cerium oxide, and cerium oxide.

Preferably, the doping ion is Ce ³⁺ ; the luminescent ceramic is YAG:Ce ³⁺ luminescent ceramic, and the scattering particles are alumina.

Preferably, the scattering particles have a particle size ranging from 100 nm to 1000 nm.

The invention also provides a preparation method of a wavelength conversion device, comprising the following steps:

Step 1: preparing a luminescent ceramic raw material according to a predetermined ratio; arranging a scattering particle raw material, the scattering particle raw material having a particle diameter of 10 nm to 5000 nm;

Step 2: mixing the luminescent ceramic raw material and the scattering particle raw material in a solvent medium, adding a binder, using a ball mill, drying the ball mill slurry, drying and then sieving to obtain a powder; The powder is uniaxially pressed by a steel mold, the pressure is 5Mpa-50Mpa, the holding time is 30s to 5min; the cold isostatic pressing is performed, and the pressure is 100Mpa-300Mpa, and the preform is obtained;

Step 3: The obtained preform is subjected to high-temperature sintering and discharging; the green body after debinding is sintered at a high temperature in a high-purity nitrogen atmosphere at a sintering temperature of 1550 ° C to 1800 ° C to obtain a luminescent ceramic, and the luminescent ceramic is polished and polished. To a predetermined thickness, a wavelength conversion device of a desired structure is obtained.

Preferably, the luminescent ceramic raw material has a particle diameter of 10 nm to 500 nm.

Preferably, the solvent medium is alcohol; the binder is polyvinyl butyral (PVB), the molecular weight is 170,000 to 250,000; the grinding ball is an alumina grinding ball; and the high temperature sintering adopts a tube furnace high temperature. Sintering; the predetermined thickness is 50 um to 500 um.

Preferably, the feedstock is in accordance with the YAG: Ce ³⁺ luminescent ceramic stoichiometry of the individual components arranged yttria, alumina, and cerium oxide; wherein the YAG: Ce ³⁺ ceramic luminescent Ce3 + doping amount of 0.01% ～1%; the scattering particle raw material is at least one of alumina, cerium oxide, and cerium oxide, and has a particle diameter of 10 nm to 5000 nm.

The present invention also provides a light-emitting device comprising an excitation light source and a wavelength conversion device according to any of the above.

The present invention also provides a projection apparatus comprising the above-described illumination apparatus.

Compared with the prior art, the present invention includes the following beneficial effects:

The wavelength conversion device provided by the invention adopts a luminescent ceramic with a lower doping amount, and has higher thermal stability than a luminescent ceramic prepared by using a phosphor with a higher doping concentration (3% or more); Solid phase sintering mode, higher doping concentration (3% or more) of luminescent ceramics; for high power excitation light applications, the light saturation performance of the low doping concentration luminescent ceramics of the present invention is higher than that of high doping luminescent ceramics . At the same time, the scattering particles with a certain particle size and volume ratio can scatter the excitation light, increase the probability of the excitation light being converted, and achieve higher wavelength conversion efficiency; and, the scattering particles have higher thermal conductivity than the luminescent ceramic substrate, and can improve The overall thermal conductivity of the wavelength conversion device further enhances the thermal stability of the wavelength conversion device.

DRAWINGS

1 is a schematic structural diagram of a wavelength conversion device according to an embodiment of the present invention;

2 is a comparison diagram of thermal stability of a wavelength conversion device according to another embodiment of the present invention.

detailed description

The embodiments of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

Example

Please refer to FIG. 1. FIG. 1 is a schematic structural diagram of a wavelength conversion device according to an embodiment of the present invention. As shown in FIG. 1, the wavelength conversion device 10 includes a luminescent ceramic 12 and scattering particles 11, and scattering particles The particles 11 are uniformly dispersed in the luminescent ceramic 12.

When the excitation light is incident on the wavelength conversion device 10, the luminescent ceramic 12 realizes the conversion of the excitation light, and the scattering particles 11 scatter the excitation light, and the scattered excitation light changes the propagation direction, thereby increasing the illuminating center of the luminescent ceramic to be converted into The probability of the laser. The conversion efficiency of the wavelength conversion device is improved as a whole.

In the present embodiment, the scattering particles have a particle diameter of 10 nm to 5000 nm, and preferably, the particle diameter ranges from 100 nm to 1000 nm. The scattering particles of this particle size have the strongest scattering of visible light, and the scattering effect is the best; especially when the scattering particles are alumina, the particle diameter of 100 nm to 1000 nm has the best scattering effect on visible light.

In this embodiment, the thickness of the luminescent ceramic is preferably 50 um to 500 um, and the strength and luminous efficiency of the luminescent ceramic are optimal at this time. When the thickness of the luminescent ceramic is too thin, its strength is poor; when the thickness of the luminescent ceramic is too thick, its luminescence loss is large, which is not conducive to the improvement of luminous efficiency, and at the same time, due to the high thermal resistance, it is not conducive to improving the irradiation of high-power excitation light. The thermal stability of the lower luminescent ceramic.

In this embodiment, the luminescent ceramic contains doping ions having a doping amount of 0.01% to 1%. It should be clear to those skilled in the art that the ratio of doping ions is a molar ratio with respect to the ions it replaces; for a YAG:Ce ³⁺ luminescent ceramic having a 1% doping concentration, the molar ratio of Ce ions to Y ions is 1%. . In this embodiment, since the direct solid phase sintering preparation method is adopted, the particle size of the prepared wavelength conversion device is small, and the direct use of the phosphor (doping ion doping concentration is higher than 3%) is directly The prepared luminescent ceramic has higher density and thermal stability. Moreover, the luminescent ceramic doped with solid phase sintering and high concentration (doped ion doping concentration higher than 3%) is also higher than the latter thermal stability; the reason is that high concentration is used. In the preparation process of ion-doped luminescent ceramics, the concentration concentration of doping ions is prone to occur in the sintered ceramics, and the doping ions are concentrated at the grain boundaries of the luminescent ceramics, resulting in uneven concentration distribution of the doping ions in the luminescent ceramics. This causes a high concentration of doped luminescent ceramics to have poor thermal stability. However, the doping concentration is too low, and although the thermal stability is good, the luminescence intensity is low. Therefore, the doping ions of the doping amount of the present invention can ensure a high luminous intensity, and also have good thermal stability and light saturation resistance. The phenomenon of light saturation described herein refers to a phenomenon in which the excitation light power does not increase or begins to decrease after the excitation light power is increased to a certain value when the luminescent ceramic realizes wavelength conversion.

In this embodiment, the luminescent ceramic is selected from garnet-structured oxide ceramics such as Ca ₃ (Al, Sc) ₂ Si ₃ O ₁₂ , (Gd, Tb, Y, Lu) ₃ (Al, Ga) ₅ O ₁₂ or One of Y ₃ Mg ₂ AlSi ₂ O ₁₂ may be used. Preferably, the luminescent ceramic is a YAG:Ce ³⁺ luminescent ceramic in which the doping ion is Ce ³⁺ . In this embodiment, the scattering particles are at least one of alumina, cerium oxide, and cerium oxide. Preferably, the scattering particles are alumina. The above-mentioned scattering particles all have good thermal conductivity, such as the thermal conductivity of alumina is 30 W/(m·K), and the thermal conductivity of the luminescent ceramic is 10 W/(m·K), so that the wavelength conversion device can be improved. The overall thermal conductivity, in turn, improves the thermal stability of the wavelength conversion device; at the same time, the scattering particles such as alumina have a binder phase in the YAG:Ce ³⁺ luminescent ceramic, which can increase the density of the luminescent ceramic and improve The strength of the wavelength conversion device; further, the formed dense surface energy can provide conditions for further processing, such as evaporation of an anti-reflection film or the like on the dense surface of the wavelength conversion device.

In a specific embodiment, the luminescent ceramic is selected from YAG:Ce ³⁺ luminescent ceramics, wherein the doping amount of Ce ³⁺ is 0.5%. The change of luminous efficiency with temperature is shown in Fig. 2. At the same time, a YAG:Ce ³⁺ luminescent ceramic with a doping amount of 3% was selected as a comparative example. As shown in Fig. 2, the luminous efficiency of the YAG:Ce ³⁺ luminescent ceramic with a doping amount of 3% is more obvious than that of the YAG:Ce ³⁺ luminescent ceramic with a doping amount of 0.5%. Therefore, as a low concentration doped YAG:Ce ³⁺ luminescent ceramic has higher thermal stability and is more suitable for the application of high power excitation light source.

It should be noted that, since the present invention adopts the method of direct solid phase sintering of raw materials to prepare luminescent ceramics, in the preparation process, the concentration concentration of doping ions is prone to occur in the sintered ceramics, and the doping ions are used in the preparation process. It is concentrated at the grain boundary of the luminescent ceramic, which causes the concentration distribution of the doping ions in the luminescent ceramic to be non-uniform, thereby causing poor thermal stability of the high-concentration doped luminescent ceramic and prone to light saturation.

The method for preparing the wavelength conversion device 10 of this embodiment includes the following steps:

Step 1: Configuring the luminescent ceramic raw material according to a predetermined ratio, the luminescent ceramic raw material has a particle diameter of 10 nm to 500 nm; and the scattering particle raw material is disposed, and the scattering particle raw material has a particle diameter of 10 nm to 5000 nm. The particle size of these raw materials is too small, the dispersion is difficult, the particle size of the raw material is too large, the sintering power is insufficient, and the density is difficult to increase.

Step 2: mixing the luminescent ceramic raw material and the scattering particle raw material in a solvent medium, adding a binder, using a ball mill to dry the ball mill slurry, and drying. After grinding and sieving, the powder is obtained; the powder is uniaxially pressed by a steel mold, the pressure is 5Mpa-50Mpa, the dwell time is 30s to 5min; the cold isostatic pressing is performed, and the pressure is 100Mpa-300Mpa, and the preform is obtained. ;

Step 3: The obtained preform is subjected to high-temperature sintering and discharging; the green body after debinding is sintered at a high temperature in a high-purity nitrogen atmosphere at a sintering temperature of 1550 ° C to 1800 ° C to obtain a luminescent ceramic, and the luminescent ceramic is polished and polished. To a predetermined thickness, a wavelength conversion device of a desired structure is obtained.

In this embodiment, the solvent medium is alcohol; the binder is polyvinyl butyral (PVB), the molecular weight is 170,000 to 250,000; the grinding ball is alumina grinding ball; the high temperature sintering is performed by high temperature sintering of the tube furnace; The thickness is 50um to 500um.

In a specific embodiment, the raw material is cerium oxide, aluminum oxide and cerium oxide arranged according to the stoichiometric ratio of each component of the YAG:Ce ³⁺ luminescent ceramic; wherein, the YAG:Ce ³⁺ luminescent ceramic Ce3+ doping amount is 0.01 %～1%; the scattering particle raw material is alumina, and the particle diameter is 10 nm to 5000 nm. Specifically, 5.7059 g of Y ₂ O ₃ (purity: 99.99%) having a particle diameter of 50 nm, and 4.8094 g of Al ₂ O ₃ (purity of 99.99%) having a particle diameter of 50 nm were weighed, and a ball mill was mixed in an alcohol medium of 20 g. At the same time, 0.4 g of polyvinyl butyral (PVB, molecular weight 170,000 to 250,000) was added as a ceramic binder, and after ball milling with alumina grinding balls for 4 to 12 hours, the ball mill slurry was dried at 70 ° C, and after drying, it was obtained. The powder is ground and sieved. The steel mold is used for uniaxial pressing, the pressure is 5Mpa-50Mpa, the holding time is 30s to 5min, and the preform is subjected to cold isostatic pressing at a pressure of 100Mpa-300Mpa. The obtained preform is subjected to high-temperature sintering and debinding to remove organic substances (mainly binders, etc.) in the green body, and the discharge temperature is 600 ° C to 1000 ° C for 4 h to 10 h. The degreased green body is sintered at a high temperature in a tube furnace to obtain a luminescent ceramic of a desired structure. When sintered, a high-purity nitrogen atmosphere (5N) is passed, and the sintering temperature is 1550 ° C to 1800 ° C for 2 h to 12 h. In the present embodiment, an excessive amount of alumina having a particle diameter of 50 nm in the raw material is used as a scattering particle raw material.

In another specific embodiment, 5.7059 g of Y ₂ O ₃ (purity 99.99%) having a particle diameter of 50 nm, 4.2941 g of 50 nm of Al ₂ O ₃ (purity of 99.99%), and 0.4294 g of Al ₂ having a particle size of 2 μm are weighed. O ₃ (purity 99.99%) was mixed with a ball mill in 20 g of alcohol medium, and 0.4 g of polyvinyl butyral (PVB, molecular weight 170,000 to 250,000) was added as a ceramic binder, and ball milling was carried out for 4 to 12 hours using an alumina grinding ball. The ball mill slurry is dried at 70 ° C. After the drying is completed, the obtained powder is ground and sieved, firstly uniaxially pressed using a steel mold, the pressure is 5 Mpa-50 Mpa, the dwell time is 30 s to 5 min, and the preform is further processed. Perform cold isostatic pressing at a pressure of 100 MPa to 300 MPa. The obtained preform is subjected to high-temperature sintering and debinding to remove organic substances (mainly binders, etc.) in the green body, and the discharge temperature is 600 ° C to 1000 ° C for 4 h to 10 h. The degreased green body is sintered at a high temperature in a tube furnace to obtain a luminescent ceramic of a desired structure. When sintered, a high-purity nitrogen atmosphere (5N) is passed, and the sintering temperature is 1550 ° C to 1800 ° C for 2 to 12 hours. In the present embodiment, the scattering particles are selected from alumina having a particle size of 2 μm.

The present invention also provides a light emitting device comprising an excitation light source and a wavelength conversion device, wherein the wavelength conversion device can have the structure and function in the above embodiments. The illuminating device can be applied to a projection and display system, such as a liquid crystal display (LCD) or a digital light path processor (DLP) projector; or can be applied to a lighting system, such as an automobile illuminator; Applied in the field of 3D display technology.

The present invention also provides a projection system including a light emitting device and a projection device, wherein the light emitting device can have the structure and function of the above-described light emitting device.

The above is only the embodiment of the present invention, and is not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformations made by the description of the invention and the drawings are directly or indirectly applied to other related technologies. The fields are all included in the scope of patent protection of the present invention.

Claims (11)

1. A wavelength conversion device, comprising:

   The wavelength conversion device includes luminescent ceramics and scattering particles, the scattering particles are uniformly dispersed in the luminescent ceramic; the scattering particles have a particle diameter of 10 nm to 5000 nm, and a volume fraction of the scattering particles in the wavelength conversion device 1% to 60%;

   The luminescent ceramic is an oxide ceramic of garnet structure;

   The luminescent ceramic contains doping ions having a doping amount of 0.01% to 1%.
2. The wavelength conversion device according to claim 1, wherein the luminescent ceramic has a thickness of 50 um to 500 um.
3. The wavelength conversion device according to claim 1, wherein said luminescent ceramic is Ca ₃ (Al, Sc) ₂ Si ₃ O ₁₂ , (Gd, Tb, Y, Lu) ₃ (Al, Ga) ₅ O At least one of ₁₂ or Y ₃ Mg ₂ AlSi ₂ O ₁₂ ;

   The scattering particles are at least one of alumina, cerium oxide, and cerium oxide.
4. The wavelength conversion device according to claim 1, wherein said dopant ion is Ce ³⁺ ; said luminescent ceramic is YAG:Ce ³⁺ luminescent ceramic, and said scattering particles are alumina.
5. The wavelength conversion device according to claim 1, wherein the scattering particles have a particle diameter ranging from 100 nm to 1000 nm.
6. A method for preparing a wavelength conversion device, comprising the steps of:

   Step 1: preparing a luminescent ceramic raw material according to a predetermined ratio; arranging a scattering particle raw material, the scattering particle raw material having a particle diameter of 10 nm to 5000 nm;

   Step 2: mixing the luminescent ceramic raw material and the scattering particle raw material in a solvent medium, adding a binder, using a ball mill, drying the ball mill slurry, drying and then sieving to obtain a powder; The powder is uniaxially pressed by a steel mold, the pressure is 5Mpa-50Mpa, the holding time is 30s to 5min; the cold isostatic pressing is performed, and the pressure is 100Mpa-300Mpa, and the preform is obtained;

   Step 3: The obtained preform is subjected to high-temperature sintering and discharging; the green body after debinding is sintered at a high temperature in a high-purity nitrogen atmosphere at a sintering temperature of 1550 ° C to 1800 ° C to obtain a luminescent ceramic, and the luminescent ceramic is polished and polished. To a predetermined thickness, a wavelength conversion device of a desired structure is obtained.
7. The method according to claim 6, wherein the luminescent ceramic raw material has a particle diameter of 10 nm to 500 nm.
8. The preparation method according to claim 7, wherein the solvent medium is alcohol;

   The binder is polyvinyl butyral (PVB), molecular weight 170,000 to 250,000;

   The grinding ball is an alumina grinding ball;

   The high temperature sintering is performed by a tube furnace at a high temperature;

   The predetermined thickness is 50 um to 500 um.
9. The preparation method according to any one of claims 6 to 7, wherein the raw material is cerium oxide, aluminum oxide and cerium oxide arranged in a stoichiometric ratio of each component of the YAG:Ce ³⁺ luminescent ceramic; , the YAG:Ce ³⁺ luminescent ceramic Ce ³⁺ doping amount is 0.01% to 1%;

   The scattering particle raw material is at least one of alumina, cerium oxide, and cerium oxide, and has a particle diameter of 10 nm to 5000 nm.
10. A light-emitting device comprising an excitation light source and the wavelength conversion device according to any one of claims 1 to 5.
11. A projection apparatus comprising the light emitting apparatus according to claim 10.

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